The present invention relates to a combine harvester comprising a chopper configured for chopping crop, which comprises a cutting cylinder fitted with chopper knives, a knife carrier fitted with counter knives, and a rasp bar arrangement, wherein the counter knives and/or the rasp bar arrangement can be or are/is moved at least partially into a partial stream passing by the chopper, and comprising a crop spreading device configured for spreading the chopped-material stream emerging from the combine harvester on the ground in the rear region of the combine harvester. There is a sensor unit configured for generating sensor data which represent at least one parameter influencing the spreading quality of the chopped-material stream emerging from the combine harvester.
The non-grain proportion harvested by a combine harvester during the harvesting operation is often spread directly on the harvested territory, for example to improve the soil quality. In this connection, it is important that the crop, i.e., the straw, is obtained and discharged in such a way that it decays easily, so that its nutritive components are available in the subsequent vegetation phase. The decay is influenced by different factors, including external influences (inter alia, weather) and the soil composition (inter alia, microorganisms) and, in particular, the spreading quality. The spreading quality is determined by different parameters of the discharged crop, for example by the shape of the crop strand on the ground behind the combine harvester or by the length of the chopped material. For example, if the crop spread on the ground is in suitably short pieces and has been spread homogeneously across the working width of the combine harvester, decay is facilitated.
Diverse solutions, which are intended to satisfy these requirements, are known from the related art. For example, EP 0 685 151 A1 discloses a system in which the wind conditions in the region of the crop spreading device of the combine harvester are determined and the discharge behavior of the spreading device is regulated according to the wind conditions. Such a system has the advantage that a spreading of the broken straw-chaff mixture conveyed out of the combine harvester that is non-uniform due to cross winds is avoided or at least reduced.
EP 1 790 207 A1 describes a system in which the spreading of the chopped-material stream emerging from the combine harvester in the rear region thereof is regulated depending on the position of the crop edge. Such a system ensures that the portion of residual material to be spread on the ground is not discharged into a crop yet to be harvested, since this would have the disadvantage that already-threshed crop would be picked up again by a combine harvester.
EP 1 514 466 A1 further discloses a combine harvester which comprises a chopper and a spreading unit and accommodates an infrared camera in the rear region thereof, the infrared camera ascertaining the spreading quality of the broken straw-chaff mixture deposited on the ground on the basis of the detected temperature distribution, wherein higher temperatures are an indicator of a greater layer thickness. On the basis of the ascertained temperature change, kinematic parameters of the chopper and the spreading device are adapted in such a way that an approximately uniform temperature distribution sets in across the spreading width, which ultimately serves as an indicator of homogeneous crop spreading and, therefore, a high spreading quality.
Finally, reference is also made, by way of example, to DE 10 2014 113 965 A1 and DE 10 2016 118 187 A1, which has not been published yet, according to which the spreading of the chopped-material stream emerging from the combine harvester takes place depending on a selectable spreading strategy and, optionally, a lower-level substrategy.
One disadvantage of the above-described systems for influencing the spreading quality is that these systems require relatively complex ancillary units which also have a correspondingly high energy requirement.